Bicycle shock assemblies with plunger operated valve arrangement

ABSTRACT

A shock absorber, which is particularly applicable to bicycles, includes a secondary chamber whose volume selectively contributes to a volume associated with a primary chamber of the shock. A piston is supported by a compression rod and cooperates with a shock tube to define the primary chamber. The secondary chamber is fluidly isolated from the primary chamber by a valve arrangement positioned proximate the piston. A plunger extends along a longitudinal length of the shock and forms or interacts with the valve arrangement such that the secondary chamber is selectively fluidly connected to the primary chamber so the primary and secondary chambers of the shock assembly contribute to the performance of the shock for a selected portion of shock travel.

BACKGROUND OF THE INVENTION

The present invention relates generally to bicycles and, moreparticularly, to shock assemblies that are constructed to facilitatecontrolled movement between movable members of a bicycle, such as aframe and a wheel assembly.

The primary structural component of a conventional two-wheel bicycle isthe frame. On a conventional road bicycle, the frame is typicallyconstructed from a set of tubular members assembled together to form theframe. For many bicycles, the frame is constructed from members commonlyreferred to as the top tube, down tube, seat tube, seat stays and chainstays, and those members are joined together at intersections commonlyreferred to as the head tube, seat post, bottom bracket and reardropout. The top tube usually extends from the head tube rearward to theseat tube. The head tube, sometimes referred to as the neck, is a shorttubular structural member at the upper forward portion of the bicyclewhich supports the handlebar and front steering fork, which has thefront wheel on it. The down tube usually extends downwardly and rearwardfrom the head tube to the bottom bracket, the bottom bracket usuallycomprising a cylindrical member for supporting the pedals and chaindrive mechanism which powers the bicycle. The seat tube usually extendsfrom the bottom bracket upwardly to where it is joined to the rear endof the top tube. The seat tube also usually functions to telescopicallyreceive a seat post for supporting a seat or saddle for the bicyclerider to sit on.

The chain stays normally extend rearward from the bottom bracket. Theseat stays normally extend downwardly and rearward from the top of theseat tube. The chain stays and seat stays are normally joined togetherwith a rear dropout for supporting the rear axle of the rear wheel. Thefront wheel assembly is commonly mounted between a pair of forks thatare pivotably connected to the frame proximate the head tube. Theforegoing description represents the construction of a conventionalbicycle frame which of course does not possess a suspension having anyshock absorbing characteristics.

The increased popularity in recent years of off-road cycling,particularly on unpaved terrain or cross-country, as well as an interestin reducing discomfort associated with rougher road riding, has madeshock absorbing systems a desirable attribute in biking system. Abicycle with a properly designed suspension system is capable oftraveling over extremely bumpy, uneven terrain and up or down very steepinclines. Suspension bicycles are less punishing, reduce fatigue, reducethe likelihood of rider injury, and are much more comfortable to ride.For off-road cycling in particular, a suspension system greatlyincreases the rider's ability to control the bicycle because the wheelsremain in contact with the ground as they ride over rocks and bumps inthe terrain instead of being bounced into the air as occurs onconventional non-suspension bicycles.

Over the last several years the number of bicycles now equipped withsuspension systems has dramatically increased. In fact, many bicyclesare now fully suspended, meaning that the bicycle has both a front andrear wheel suspension systems. Front suspensions were the first tobecome popular. Designed to remove the pounding to the bicycle frontend, the front suspension is simpler to implement than a rearsuspension. A front suspension fork is easy to retrofit onto an oldermodel bicycle. On the other hand, a rear suspension will increasetraction and assist in cornering and balance the ride.

During cycling, as the bicycle moves along a desired path,discontinuities of the terrain are communicated to the assembly of thebicycle and ultimately to the rider. Although such discontinuities aregenerally negligible for cyclists operating on paved surfaces, ridersventuring from the beaten path frequently encounter such terrain. Withthe proliferation of mountain biking, many riders seek the moretreacherous trail. Technology has developed to assist such adventurousriders in conquering the road less traveled. Wheel suspension systemsare one such feature.

Even though suspension features have proliferated in bicycleconstructions, the performance of the suspension as well as thestructure of the bicycle are often limited to or must be tailored tocooperate with the structure and operation of the shock. Commonly, asthe bicycle traverses uneven terrain or during aggressive riding, theoverall length of the shock shortens and thereby compresses a volume ofair or gas enclosed by the shock. As the shock continues to shorten, apiston supported by a compression rod continues to compress the fluid asthe size of the chamber continues to get smaller. As compression of thegas continues, the shock becomes progressively more resistive toallowing continued shortening of the shock. That is, the compressibilityof the gas contained in the shock results in the shock feelingprogressively stiffer as the overall shock length continues to shorten.Such operation detracts from the range of movement of the shock whereina desired shock performance can be attained and/or requires greatershock lengths to accommodate a desired range of motion dampeningoperation.

Therefore, there is a need for a shock system that is more responsive toloading across a wider range of the overall compressibility of theshock. There is a further need for a shock system that can provide avariety of shock performances without otherwise interfering with themounting of the shock to the bicycle.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a shock or shock absorber for a bicyclethat overcomes one or more of the drawbacks discussed above. A shockabsorber according to one aspect of the invention includes a primarychamber and a secondary chamber that are separated by a valve assemblyor valve arrangement. A piston is supported by a compression rod andcooperates with a shock tube to define the primary chamber. Thesecondary chamber is positioned on an opposite side of the piston andfluidly separates the primary and secondary chambers. A skewer orplunger extends a longitudinal length of the shock and cooperates withan opening formed in the piston to form the valve arrangement ormanipulate a piston mounted valve assembly such that the secondarychamber is selectively fluidly connected to the primary chamber so as toalter the performance of the shock. Such a construction allows thesecondary chamber to contribute to the shock performance only after ashock has undergone a selected displacement.

Another aspect of the invention usable with one or more of the featuresof the above aspect discloses a shock assembly for a bicycle. The shockassembly includes a first sleeve and a second sleeve that is engagedwith the first sleeve such that the first sleeve and the second sleeveare connected in a telescopic manner. A piston is enclosed by the firstand second sleeves and defines a first volume on one side of the pistonand a second volume on an opposite side of the piston. A valvearrangement or assembly is provided between the first and second volumesand configured to fluidly separate the first volume from the secondvolume. The shock assembly includes a plunger that is configured tocooperate with the piston to selectively open the valve arrangement tofluidly connect the second volume to the first volume.

Another aspect of the invention usable with one or more of the featuresassociated with the above aspects discloses a method of altering thein-use performance of a bicycle shock. The method includes forming afirst chamber and a second chamber that are separated by a piston. Thefirst and second chambers are fluidly connectable as a function oftranslation of a cap tube relative to a leg tube by translating aplunger through an opening formed in the piston.

Another aspect of the invention useable with one or more of the aboveaspects discloses a bicycle suspension system having a cap tube that isattached to a first bicycle structure and a leg tube that is attached toa second bicycle structure. The cap tube and the leg tube aretelescopically associated to allow translation between the first andsecond bicycle structures. A piston is disposed in a cavity enclosed bythe cap and leg tubes for enclosing a first volume whose pressureincreases as distal ends of the cap and leg tubes move toward oneanother and separating the first volume from a second volume. A stemextends between the piston and a distal end of one of the leg tube andthe cap tube. A plunger cooperates with the piston to fluidly connectthe first and second volumes when the distal ends of the cap and legtubes are a selected distance apart.

Preferably, the plunger or skewer extends from one of the first orsecond shock sleeves or tubes. Alternatively, the skewer can also extendfrom the valve. In various embodiments, the plunger is shaped tocooperate with an opening in the piston in sealing and non-sealingmanners. Alternatively, a valve assembly can be supported by the pistonand constructed to include a spring that biases the valve to a closedposition and whose bias is overcome by the plunger or skewer. One aspectof supporting the spring includes providing a rib that extends from aninterior surface of the compression rod or stem such that the spring isdisposed between the rib and the valve.

Another aspect of the invention combinable with one or more of the aboveaspects includes constructing the plunger to include a bypass sectionthat facilitates fluid communication between the first and secondchambers via a space formed between the plunger and the piston orthrough a passage within the plunger. Preferably, the bypass section isprovided to allow fluid communication between the first and secondvolumes when the top tube and leg tube are positioned away from a fullyextended and a fully compressed orientation. More preferably, the volumeof the plunger and/or a compression rod that supports the pistoncontributes to the volume of the second chamber.

Another aspect of the invention combinable with one or more of the aboveaspects includes providing another valve or fill valve assembly thatfluidly separates the interior volume of the shock from atmosphere. Inone aspect, the fill valve assembly is supported by one of the first andsecond sleeves for pressurizing the first volume. Preferably, the fillvalve is disposed between the volume enclosed by the shock andatmosphere. In a further aspect, the fill valve assembly and the pistonvalve arrangement are connected so that the fill valve assembly can beselectively fluidly connected to either of the first or second volumesof the shock assembly by manipulation of the fill valve assembly.

It is appreciated that the aspects and features of the inventionsummarized above are not limited to any one particular embodiment of theinvention. That is, many or all of the aspects above may be achievedwith any particular embodiment of the invention. Those skilled in theart will appreciate that the invention may be embodied in a mannerpreferential to one aspect or group of aspects and advantages as taughtherein. These and various other aspects, features, and advantages of thepresent invention will be made apparent from the following detaileddescription and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate preferred embodiments presently contemplated forcarrying out the invention.

FIG. 1 is a side elevation view of a bicycle equipped with a shockassembly according to the present invention;

FIG. 2 is a side elevation view of the steerer assembly and shockassembly removed from the bicycle shown in FIG. 1;

FIG. 3 is a front elevation view of the assembly shown in FIG. 2;

FIG. 4 is a cross-sectional view of the shock assembly taken along line4-4 shown in FIG. 3;

FIG. 5 is a detailed view of a portion of the shock assembly shown inFIG. 4 showing the shock compressed a sufficient degree to operate thevalve assembly that is internal thereto;

FIG. 6 is a view similar to FIG. 4 of a shock assembly according toanother embodiment of the invention;

FIG. 7 is a view similar to FIG. 5 of the shock assembly shown in FIG.6;

FIG. 8 is a view similar to FIG. 4 of a shock assembly according to yetanother embodiment of the invention;

FIG. 9 is a view similar to FIG. 5 of the shock assembly shown in FIG.8;

FIG. 10 is a detailed view of a fill valve assembly of the shockassembly shown in FIGS. 8 and 9 and having an operator that is movableby a user;

FIG. 11 a is a detailed view of an example of a telescopic and rotatableconnection between the fill valve assembly and a piston supported valveof the shock assembly shown in FIGS. 8 and 9;

FIG. 11 b is a view similar to FIG. 11 and shows a cross-section of thefill valve assembly that is generally transverse to the view shown inFIG. 11 a;

FIG. 12 is a perspective view of the fill assembly shown in FIGS. 11 aand 11 b and shows the engagement of the oppositely positioned guidepins with the mount body that is positioned about the moveable operatorof the fill valve assembly;

FIG. 13 is a view similar to FIGS. 11 a and 11 b and shows a fill valveassembly according to another embodiment of the invention

FIG. 14 is a view similar to FIG. 4 of a shock assembly according toanother embodiment of the invention;

FIG. 15 is a view similar to FIG. 5 of the shock assembly shown in FIG.14;

FIG. 16 is a view similar to FIG. 15 of a shock assembly according toanother embodiment of the invention;

FIG. 17 is a view similar to FIG. 14 of a shock assembly according toanother embodiment of the invention;

FIG. 18 is a view similar to FIG. 15 of the shock assembly shown in FIG.17;

FIG. 19 shows various compression rods having a swaged section that canbe used with the various shock assembly embodiments described above;

FIG. 20 is shows the flow performance of the swaged compression rodsshown in FIG. 19;

FIG. 21 graphically shows the shock performance of shock assembliesequipped with differently shaped swaged compression rods shown in FIG.19;

FIG. 22 shows the flow performance of a vented compression rod that canbe used with the various shock assembly embodiments described above; and

FIG. 23 graphically shows the speed sensitivity performance that can beachieved with the shock assemblies according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a bicycle 30 having a frame assembly 32 equipped with atleast one suspension system 34 that includes a shock absorber, shockassembly, or shock 40 that is constructed according to at least one ofthe embodiments of the present invention according to the presentinvention. Bicycle 30 includes a seat 42 and handlebars 44 that areattached to frame assembly 32. A seat post 46 is connected to seat 42and slidably engages a seat tube 48 of frame assembly 32. A top tube 50and a down tube 52 extend in a forward direction relative to seat tube48 to a head tube 54 of frame assembly 32. Handlebars 44 are connectedto a stem 56 that passes through head tube 54 and engages a fork crown58. A pair of forks 60 extend from generally opposite ends of fork crown58 and support a front wheel assembly 62 at an end of each fork or afork tip 64. Fork tips 64 engage generally opposite sides of an axle 66that cooperates with a hub 68 of front wheel assembly 62. A number ofspokes 70 extend from hub 68 to a rim 72 of front wheel assembly 62. Atire 74 extends about rim 72 such that rotation of tire 74, relative toforks 60, rotates rim 72 and hub 68.

Preferably, each fork 60 is provided as a shock absorber 40 so as toallow translation of axle 66 of front wheel assembly 62 relative toframe assembly 32. Although each fork 60 is shown as having respectiveends secured proximate one of frame assembly 32 and axle 66, it isappreciated that the hereafter description of shocks according to one ormore of the embodiments of the present invention are equally applicableto bicycle rear wheel suspension features. One such rear wheelsuspension system is disclosed in applicants co-pending U.S. PatentApplication Publication No. 2008/0252040, the disclosure of which isincorporated herein.

Bicycle 30 includes a front brake assembly 76 having an actuator 78attached to handlebars 44. Brake assembly 76 includes a caliper 80 thatpresses a pair of oppositely positioned brake pads 81 into a brake wall82 of rim 72 to provide a stopping or slowing force to front wheelassembly 62. Bicycle 30 includes a rear wheel assembly 84 that alsoincludes a brake assembly 86 having a caliper 90 that presses a pair ofbrake pads into a brake wall 88 of a rear wheel 92. Rear wheel 92 ispositioned generally concentrically about a rear axle 94.Understandably, one or both of front wheel assembly 62 and rear wheelassembly 84 could be equipped with other brake assemblies orarrangements such as disc brake assemblies.

A seat stay 102 and a chain stay 104 extend rearward from seat tube 48and offset rear axle 94 of rear wheel assembly 84 from a crankset 106.Crankset 106 includes oppositely positioned pedals 108 that areoperationally connected to a chain 110 via a chain ring or sprocket 112.Rotation of chain 110 communicates a drive force to rear wheel assembly84 of bicycle 30. A gear cluster 116 is positioned proximate axle 94 andis engaged by chain 110. Gear cluster 116 is generally concentricallyorientated with respect to rear axle 94 and includes a number ofvariable diameter gears. Gear cluster 116 is operationally connected toa hub 118 of rear wheel 92 of rear wheel assembly 84. A number of spokes120 extend radially between hub 118 and a rim 122 of rear wheel assembly84. As is commonly understood, rider operation of pedals 108 driveschain 110 thereby driving rear wheel 92 which in turn propels bicycle30.

Understandably, the construction of bicycle 30 shown in FIG. 1 is merelyexemplary of a number of bicycle configurations usable with the shockassemblies of the present invention. That is, whereas bicycle 30 isshown as having only a front wheel shock assembly, it is envisioned thatshock assemblies according to the present invention provide either frontor rear wheel shock or vibration isolation. It is further appreciatedthat the shock constructions of the present invention are equallyapplicable to street or road bikes as well as other bicycleconfigurations such as mountain and/or dirt bikes. It is furtherappreciated that the shock assemblies of the present invention may beapplicable to any of a number of vehicle configurations in addition tothe bicycle configuration shown.

Referring to FIGS. 2 and 3, bicycle 30 includes two shock assemblies 40that are each secured to fork crown 58 such that shock assemblies 40form the forks 60 of bicycle 30. A first end 130 of each shock assembly40 is secured to a respective shoulder or arm 132 of fork crown 58. Asecond end 134 of each shock assembly 40 forms fork tip 64 of each shockassembly. Stem 56 is generally centrally positioned with respect to thelongitudinal axis of each fork assembly 40. Stem 56 forms a steerer tubeand extends from fork crown 58 in a direction generally opposite shockassemblies 40. Stem 56 engages frame 32 of bicycle 30 such that rotationof stem 56 about a longitudinal axis 124 of stem 56 rotates forks 60about axis 124 so as to steer bicycle 30.

Each shock assembly 40 includes a first sleeve, tube, or cap tube 140that cooperates with a second sleeve, tube, or leg tube 142. Preferably,each cap tube 140 and leg tube 142 are telescopically associated. Anoptional arch 144 (FIG. 3) connects each leg tube 142 of adjacent shockassemblies 40 and defines a wheel cavity 146 between the adjacent forks60. Each fork tip 64 includes a dropout or opening 147 that receives arespective end 152, 154 of axle 66. During loading and unloading of thewheel of bicycle 30, cap tubes 140 and leg tubes 142 translate relativeto one another, indicated by arrow 150, thereby altering the distancebetween fork tips 64 and arms 132 of fork crown 58. Shock assemblies 40absorb and dissipate a portion of the energy associated with an impact.

FIGS. 4-9 show various embodiments of shock assemblies 40 that aredirected to a first general concept of implementing the presentinvention whereas FIGS. 13-22 are generally directed to embodiments ofthe present invention that relate to a second concept for implementingthe present invention. Comparing the various embodiments shown in FIGS.4-9 and FIGS. 13-22, it is appreciated that shock assemblies 40 includea valve arrangement or valve assembly that is supported by the piston ofthe shock assemblies whereas the shock assemblies shown in FIGS. 13-22include a valve arrangement or valve assembly that is formed by thecooperation of the construction of the plunger with the construction ofthe piston. As used herein, the terms valve arrangement, valve assembly,and valve capture all such configurations and connote the fluidlyseparable interaction between a first or primary chamber of a shockassembly and a second or secondary chamber of the shock assembly.

With respect to FIGS. 4-9, each shock assembly 40 includes a cap tube140 that slidably engages a leg tube 142. A hollow stem or compressionrod 160 extends longitudinally along the leg tube 142 and includes apiston 162 that is supported at an end thereof. A moveable valve 164 isformed through piston 162 and selectively separates a volume generallyabove the piston and a volume enclosed by the compression rod.

Each shock assembly 40 includes a skewer or plunger 166 that is alignedwith valve arrangement, valve assembly, or valve 164 so as toselectively fluidly connect a first cavity or chamber 168 and a secondcavity or chamber 170 of each shock assembly 40. As alluded to above,each first chamber 168 and the second chamber 170 are selectivelyfluidly connected/separated by valve 164 that is supported by piston162. First chamber 168 is generally defined as the area or volumeenclosed by cap tube 140, piston 162, and a cap tube cap 172. It isappreciated that cap tube 140 and cap tube cap 172 be formed as aunitary tube having one closed end. That is, it is appreciated that captube cap 172 could be formed integrally with the body of cap tube 140.Second chamber 170 is defined as the area generally enclosed bycompression rod 160 and the valve 164 supported by piston 162.

Still referring to each of the piston assemblies 40, a spring 176 biasesvalve 164 to a closed position (as shown in FIGS. 4, 6, and 8) so as tofluidly separate first chamber 168 from second chamber 170. Upon adesignated displacement of dropouts 64 relative to arm 132 of fork crown58, plunger 166 interacts with other structure of shock assembly 40(such as structure associated with tube cap 172 as shown in FIG. 5)and/or interacts with valve 164 (as shown in FIGS. 7 and 9) such thatfirst chamber 168 and second chamber 170 are fluidly connected to oneanother such that second chamber 170 contributes to the performance ofshock assembly 40 when valve 164 is open.

Referring to shock assembly 40 shown in FIGS. 4 and 5, compression rod160 offsets piston 162 from a first end 180 of leg tube 142 of shockassembly 40. Cap tube 140 is slidably positioned between piston 162 andleg tube 142. A seal 184 is positioned between the interface of cap tube140 and leg tube 142 proximate a second end 182 of leg tube 142. Apiston seal 186 is disposed between piston 162 and an interior surface188 of cap tube 140. During shortening of the overall length of theshock assembly 40, piston 162 compresses the gas contained in firstchamber 168 of shock assembly 40 thereby resisting or absorbing aportion of the energy associated with the compression stroke of theshock assembly. A bumper assembly 190 is disposed between piston 162 anddropout 64 and dampens motion as shock assembly 40 approaches a fullylengthened orientation during recovery from aggressive compressions.

Referring to FIG. 5, plunger 166 extends from a stem 190 of valve 164. Avalve head 192 cooperates with a valve seat or seal 194 positioned aboutan opening 196 between first chamber 168 and second chamber 170. Plunger166 passes through opening 196 and extends longitudinally along firstchamber 168 toward tube cap 172. Plunger 166 includes a stop, lip, orhead portion 198 that is sized to contain spring 176 generally betweenhead portion 198 and an upper surface or face 200 of piston 162. Spring176 normally biases valve head 192 into engagement with valve seat 194thereby closing opening 196 and fluidly separating first chamber 168from second chamber 170.

During compression loading of shock assembly 40, piston 162 translatesto a position nearer arm 132 and compresses the volume of gas containedin first chamber 168. At a selected distance, indicated by arrow 202,plunger 166 contacts tube cap 172 of shock assembly 40. Continuedtranslation of piston 162 in an upward direction toward tube cap 172translates valve head 192 out of engagement with valve seat 194 in adownward direction, indicated by arrow 204. As valve head 192 disengagesvalve seat 194, gas compressed in first chamber 168 via the displacementof piston 162 relative to tube cap 172 passes through opening 196,indicated by arrows 206, and flows into second chamber 170. Accordingly,when valve 164 is opened, first chamber 168 and second chamber 170 bothcontribute to the operating performance of shock 40. Until valve 164opens, of first and second chambers 168, 170, only first chamber 168contributes to the performance of shock assembly 40 as second chamber170 maintains a fixed shape and is fluidly isolated from first chamber168.

Shock assembly 40 includes another valve or fill valve 210 that issupported by tube cap 172. Preferably, fill valve 210 is a Schradervalve as is commonly understood in the art. Fill valve 210 fluidlyseparates first chamber 168 from atmosphere. Referring to FIG. 4, duringinitial configuration of shock assembly 40, first chamber 168 can bepressurized to a desired value via fill valve 210. After an oscillationof shock assembly 40 that is sufficient to open valve 164 supported bypiston 162, first chamber 168 and second chamber 170 attain a pressureassociated with compressing the at-rest volume of gas of first chamber168 to the combined volume of first chamber 168 and second chamber 170when piston 162 attains distance 202. The overall performance of shockassembly 40 can be tailored to a riders' preference via the initialpressurization of first chamber 168. Additionally, regardless of theinitial pressurization, shock assembly 40 also avoids overly progressiveperformance or non-responsive operation of the shock assembly at nearerfull displacements by physically altering the size of the useable volumeof the shock assembly. That is, the addition of second chamber 170 tothe volume of first chamber 168 at an intermediate shock length allowsfor greater utilization of the shock across a wider range of availabledisplacement lengths.

FIGS. 6 and 7 show another embodiment of shock assembly 40 that providesthe same attributes in a slightly different manner. As shown in FIG. 6,spring 176 extends in a downward direction within second chamber 170formed by compression rod 160. A projection, stop, or lip 220 extendsfrom an interior wall 222 of compression rod 160 and engages an end 224of spring 176 without fully unduly restricting movement of gas in secondchamber 170.

Valve 164 includes a valve stem 228 that extends downward from a valvehead 226. A second end 230 of spring 176 engages valve head 226 andbiases valve head 226 into engagement with a valve seat 232. Valve seat232 is formed in a downward facing side 234 of piston 162. An optionalguide 233 is formed in piston 162 proximate valve 164 and is shaped toguide plunger 166 into engagement with valve 164. Cap tube 140cooperates with a seal 236 and a piston seal 238 such that cap tube 140telescopically cooperates with leg tube 142. Seal 236 cooperates with anexterior wall 240 of cap tube 140 and piston seal 238 cooperates with aninterior wall 242 of cap tube 140. Such a configuration provides for thesliding and sealed interaction between cap tube 140, leg tube 142, andpiston 162. A bumper assembly 246 that is similar to bumper assembly 190is disposed about compression rod 160 generally below piston 162 anddampens movement nearer the full lengthening of shock assembly 40 shownin FIGS. 6 and 7.

Rather than extending from valve 164 supported by piston 162, plunger166 of the shock assembly shown in FIGS. 6 and 7 extends in a downwarddirection from an end 248 of shock assembly 40. End 248 of shockassembly 40 is secured to arm 132 of fork crown 58. Preferably, plunger166 is concentrically oriented with respect to valve 164, cap tube 140,and leg tube 142. Plunger 166 is aligned with valve 164 such that adistal end 260 of plunger 166 interacts with valve 164 to selectivelyopen a passage 262 formed through piston 162. Passage 262 fluidlyconnects first chamber 168 and second chamber 170 and is selectivelyclosable by operation of valve 164. Another valve or fill valve 264 isattached to tube cap 172 and selectively isolates first chamber 168 fromatmosphere 266. Preferably, fill valve 264 is provided as a Schradervalve and is configured to allow first chamber 168 to be filled with airor another gaseous fluid.

Referring to FIG. 7, when piston 162 is moved to be within a givendistance, indicated by arrow 270, from tube cap 172 of shock assembly40, plunger 166 interacts with valve 164 and overcomes the bias ofspring 176 thereby opening passage 262 between first chamber 168 andsecond chamber 170. When valve 164 is opened, the volume of firstchamber 168 and second chamber 170 both contribute to the performance ofshock assembly 40. Prior to obtaining the rate of compression associatedwith distance 270, only first chamber 168 contributes to the performanceof shock assembly 40. Accordingly, shock assembly 40 reduces thestiffness associated with performance of shock assembly 40 duringtranslation of piston 162 within distance 270.

Similar to the shock assembly shown in FIGS. 4-5, the shock assemblyshown in FIGS. 6 and 7 maintains generally equal pressures within firstchamber 168 and second chamber 170 only when plunger 166 contacts oropens valve 164. After unloading of a compression stroke wherein valve164 was opened, the pressure of second chamber 170 is maintained at thelevel associated with valve 164 closing and the pressure of firstchamber 168 continues to decrease as piston 162 continues to translatein a downward direction, indicated by arrow 272. The shock assembly 40shown in FIGS. 6 and 7 is as responsive to compression loads as theshock assembly shown in FIGS. 4 and 5. Each such shock assemblies areequally responsive to operation across a wider range of the availablelength of translation between the cap tube and the leg tube.

FIGS. 8-9 show another embodiment of shock assembly 40. The constructionof the shock assembly shown in FIGS. 8-9 more nearly resemble the shockassembly shown in FIGS. 6 and 7 as compared the shock assembly shown inFIGS. 4 and 5. Accordingly, similar structures have been given similarreference numbers and understandably operate in a similar manner.

As shown in FIGS. 8 and 9, plunger 166 extends in a downward directionfrom tube cap 172. Plunger 166 interacts with valve 164 in a mannersimilar to that described above with respect to FIGS. 6 and 7. Unlikethe embodiment shown in FIGS. 6 and 7, the shock assembly shown in figseight to 10 includes a fill valve assembly 280 wherein second chamber170 is fluidly disposed between fill valve assembly 280 and firstchamber 168.

As shown in FIGS. 9 and 10, fill valve assembly 280 includes a fillvalve 282, such as a Schrader, American valve, or Presta valve, that isattached to an operator 284. Operator 284 movably cooperates with amount body 286 that is attached to leg tube 142. Operator 284 isrotatably connected to mount body 286 such that a passage or fillpassage 320 formed in operator 284 can be selectively aligned with afirst passage 322 that is fluidly connected to second chamber 170 and asecond passage 324 that is fluidly connected to first chamber 168. Anumber of seals or O-rings 326, 328, 330 fluidly isolate each ofpassages 322, 324 and operator 284 relative to mount body 286. Such aconstruction allows a user to provide a desired pressure to each offirst chamber 168 and second chamber 170 via rotation of operator 284,as indicated by arrow 332. A retainer, such as a snap ring, E or C-ring,or the like 334 cooperates with a groove 336 formed in mount body 286and secures operator 284 longitudinally with respect to mount body 286.Although fill valve assembly 280 is operable to provide selective fluidconnectivity with each of first and second chambers 168, 170, fill valveassembly 280 maintains fluid isolation between each of first and secondchambers 168, 170 such that fluid connectivity between the respectivechambers is determined by the relative translation of the cap tube andleg tube of the respective shock assembly.

FIGS. 11 a, 11 b, and 12 show a fill valve assembly 350 according toanother embodiment of the invention. Fill valve assembly 350 includes afill valve 352, such as a Schrader, American valve, or Presta valve,that is attached to an operator 354. Operator 354 movably cooperateswith a mount body 356 that is attached to one of cap tube 140 or legtube 142. Operator 354 is rotatably and linearly translatable relativeto mount body 356. Operator 354 includes a passage or fill passage 358that can be selectively fluidly connected to first or second chambers168, 170. Operator 354 is moveable between a “down position” and an “upposition” so that either of the first chamber 168 or the second chamber170 of the shock assembly can be selectively fluidly connected toatmosphere via fill valve 352. Such a construction allows a user toindividually pressurize each of the first and second chambers 168, 170.

When located in the “down position”, fill passage 358 is directlyexposed to second chamber 170 such that fill valve assembly 352 isfluidly connected to second chamber 170. Still referring to FIGS. 11 aand 11 b, when in the “down position”, fill passage 358 is fluidlyisolated from a passage or port 360 that passes through mount body 356.As shown in FIGS. 11 b and 12, a pair of pins 364 are engaged with, andextend beyond an interior surface of mount body 356. A distal end 357 ofeach pin 364 cooperates with a groove or generally L-shaped channel 366formed in operator 356. The cooperation of pins 364 and channels 366allows operator 354 to both rotate and translate in a longitudinaldirection relative to mount body 356.

When operator 354 is translated toward the “up position”, operator 354translates in an outward direction, indicated by arrow 369, relative toa bottom 370 of each channel 366 as operator 354 translates along pins364. When in the “up position” port 358 (FIG. 11 a) is generallylongitudinally aligned with passage 360 thereby fluidly connecting valveassembly 352 with first chamber 168. When in the “down position” asshown in FIGS. 11 a, 11 b, and FIG. 12, channel 366 includes a catch 367formed at an end of channel 366 that is generally opposite bottom 370 ofchannel 366. The interaction of pins 364 and catch 367 preventtranslation of operator 354 in a longitudinal direction when operator354 is positioned in the “down position”. Catch 367 and pins 364 resistupward translation of operator 354 during user interaction with valveassembly 352 when operator 354 is located in the “down position” andresists upward translation of operator 354 relative to mount body 356due to pressurization of the second chamber 170. Such a constructionallows the user to pressurize second chamber 170 without being requiredto bias operator 354 in a downward direction against bias associatedwith the air pressure contained within the first or second chamber. In asimilar manner, when operator 354 is translated to the “up position”,air pressure contained within the first or second chamber biasesoperator 354 upward. Said in another way, operator 354 is biased towardthe “up position” by the pressurization of first and second chambers168, 170 without a catch or other position retention assembly.

As best shown in FIGS. 11 a and 11 b, fill valve assembly 350 includes anumber of seals, such as O-rings, 372, 374, 376 that provide a sealedinteraction between operator 354, mount body 356, and compression rod160. Seals 372, 374, 376 allow valve assembly 352 to be selectivelyfluidly connected to first chamber 168 and second chamber 170 and in amanner that maintains the fluid isolation therebetween. User rotation ofoperator 354, indicated by arrow 373, relative to mount body 356 allowspins 364 to be selectively engaged and disengaged from catch 367 therebyallowing selective longitudinal translation of operator 354 relative tomount body 356 and selective fluid connectivity of fill port 358 withfirst and second chambers 168, 170. Like fill valve assembly 280,although fill valve assembly 350 is operable to provide selective fluidconnectivity with each of first and second chambers 168, 170, fill valveassembly 350 also maintains fluid isolation between each of first andsecond chambers 168, 170 such that fluid connectivity between therespective chambers is determined by the relative translation of the captube and leg tube of the respective shock assembly.

FIGS. 13-18 show shock assemblies according to further embodiments ofthe invention. Unlike the heretofore embodiments that include agenerally solid bodied plunger or skewer that interacts with a valvearrangement, valve assembly, or valve that is supported by the piston ofthe shock assembly, the forthcoming shock assemblies include a generallyhollow cored skewer or plunger that cooperates with the piston of theshock assembly in a manner wherein the cooperation of the skewer orplunger with the piston forms the valve arrangement, valve assembly, orvalve that provides the selective fluid connectivity between the firstand second chambers. However, similar to the previously disclosed shockassemblies, translation of the top tube relative to the bottom tubeselectively fluidly connects the first and second chambers of therespective shock assemblies. Additionally, the forthcoming shockassemblies are also constructed to allow a user to selectively configurethe pressurization of each of a first chamber and a second chamber so asto adjust the spring performance of the shock assemblies. Some of thefollowing embodiments also allow independent initial pressurization ofeach of the respective chambers whereas others require an initialoscillation of the shock assembly to generate the initial pressuredifferential between the first and second chambers.

Referring to FIG. 13, a shock assembly 400 according to anotherembodiment of the invention includes a compression tube 402 that has oneor more vents or ports 404, 406, 408, 410 formed through a sidewall 414of the tube 402. Tube 402 cooperates with an opening 416 formed througha piston 418 of shock assembly 400 and provides the valved interactionbetween the first and the second chambers of the shock assembly. A seal420 is disposed between piston 418 and tube 402. Tube 402 includes agenerally hollow cavity 420 that allows fluid communication betweenports 404, 406, 408, and 410 of tube 402. An offset or space ismaintained between at least two of ports 404, 406, 408, and 410 along alongitudinal length of tube 402.

During oscillation of a top tube 424 relative to a bottom tube 426 ofshock assembly 400, tube 402 translates in a direction aligned with thelongitudinal axis of the shock so that, at a desired shock length, alower port is fluidly connected to a second chamber 428 and another portis fluidly connected to the primary of first chamber 430. Referring toFIGS. 13 and 22, when ports 404, 406 and ports 408, 410 are positionedon generally opposite sides of piston 418, first and second chambers430, 428 are fluidly connected via passage 420 of tube 402 as indicatedby arrows 444 shown in FIG. 22. Such a construction allows the volumesof passage 420, first chamber 430 and second chamber 428 to contributeto the spring performance of shock assembly 400.

As shown in FIG. 22, during extension of shock assembly 400, tube 402translates in an upward direction, indicated by arrow 446, relative topiston 418 so that each of ports 404, 406, 408, 410 are positioned on acommon side of piston 418. As tube 402 translates in direction 446, thevolume of second chamber 428 is fluidly isolate from the volume of firstchamber 430 and the volume 420 of tube 402. The pressure of secondchamber 428 remains generally unchanged when each of ports 404, 406,408, 410 are positioned on a common side of piston 418 even though toptube 424 continues to translate in a direction away from bottom tube426. However, the pressure of first chamber 430 reduces with continuedupward translation of tube 402 relative to piston 418 as the volumeassociated with first chamber 430 continues to increase.

It is appreciated that the performance of shock assembly 400 can beuniquely configured by the altering the distance 422 between the upperand lower ports, by altering the position of the lowermost port alongtube 402 so as to alter the relative position of top tube 424 relativeto bottom tube 426 that results in fluid connectivity between the firstand second chambers 430, 428, and/or by changing the size and/or numberof ports provided in tube 402. It is further appreciated that first andsecond chambers 430, 428 of shock assembly 400 can be pressurized bygenerating an initial “over pressure” condition in first chamber 430 andoscillating the shock assembly so that the first and second chambers arefluidly connected via ports 404, 406, 408, 410 similar to the mannerdescribed above.

As shown in FIG. 13, shock assembly 400 includes a fill valve assembly423 that allows a user to pressurize the internal cavities of shockassembly 400. In a first embodiment, fill valve assembly 423 is fixedlysecured to shock assembly 400 so that the entirety of the initialpressurization of shock assembly 400 is directed to first chamber 430.The initial oscillation of shock assembly 400 allows a portion of thevolume of gas initially provided to first chamber 430 to occupy secondchamber 428. Those skilled in the art will appreciate that after such aninitial oscillation, the pressure of second chamber 428 will be higherthan the pressure of first chamber 430 when shock assembly 400 is in arest configuration.

As mentioned above, it is further appreciated that the pressuredifferential between first and second chambers 430, 428 can be uniquelyconfigured by altering the position of the lowermost ports 408, 410along the longitudinal length of tube 402 relative to the total traveldistance of shock assembly 400. That is, isolating the lowermost portsof tube 402 from the second chamber 428 at a point nearer the fullyextended length of shock assembly 400 will provide a second chamberpressure that is nearer the first chamber pressure as compared toisolating the second chamber from the first chamber at positions thatare nearer to the fully compressed length of shock assembly 400.

It is envisioned that shock assembly 400 could also be provided in amanner that allows a user to individually pressurize each of first andsecond chambers 430, 428. Referring back to FIG. 13, fill assembly 423could be provided with a valve assembly 449 that is supported by amovable operator 450 that cooperates with a mount body 452 in a mannersimilar to that described above with respect to FIGS. 11 and 12. Asshown in FIG. 13, an optional tube 454 extends from operator 450 andpasses through passage 420 of tube 402. A distal end 460 of optionaltube 454 includes a port 464 that can be selectively fluidly connectedto second chamber 428 when operator 450 is in a “down position” andfluidly connected to passage 420 of tube 402 when operator 450 is an “upposition”.

A seal 466 is disposed between tube 402 and optional tube 454. Optionaltube 454 is translatable so that port 464 can be selectively positionedabove or below seal 466. When port 464 is positioned above seal 466, gasprovided via fill valve assembly 423 is communicated only to firstchamber 430 via passage 420 and ports 404, 406, 408, 410. When port 464is positioned below seal 466, provided via fill valve assembly 423 iscommunicated only to second chamber 428. Optional tube 454 allows theuser to selectively fill the two separate chambers with a single fillvalve assembly and in a manner that does not require an initialoscillation of the shock assembly. Understandably, a fill valve assemblycould be provided for each of first and second chambers 430, 228 andallow the individual pressurization of each of the respective chambersof the shock assembly.

It is appreciated that optional tube 454 allows the user to individuallypressurize each of first and second chambers 430, 428 without initialoscillation of shock assembly 400 in a manner similar to the embodimentsdescribed above. It is further appreciated that the tube 454 cancontribute to the performance and/or operation of a shock assemblyequipped therewith manners that allow selective pressurizing of thefirst and second chambers, facilitate fluid connectivity between thefirst and second chambers, and allow fluid isolation between therespective plunger and the volumes of the respective first and secondchambers. Some of the disclosed shock assemblies include a hollow,continuous, and open-ended plunger, such as the swaged and/ormechanically grooved plungers 840, 880, such that the hollow plungerextends into the second volume thereby allowing a user to selectivelyfill the second chamber or volume of the shock assembly (such as withfill valve assembly 352). As is further understood, for thoseembodiments that include a ported plunger, such as plunger 402, a distalend of the ported plunger is closed, plugged, and/or sealed so as tomaintain fluid separation between the first and second chambers of theshock except for when the respective ports are positioned on generallyopposite sides of the respective piston during oscillation of the shockassembly.

FIGS. 14 and 15 show a shock assembly 500 according to anotherembodiment of the invention. Shock assembly 500 includes a top tube 502,a bottom tube 504, a compression rod 506, a tube skewer or plunger 508,a piston 510, and a sleeve 512. Plunger 508 extends from a fill valveassembly 514 and slidably cooperates with an opening 516 formed inpiston 510. A seal 518 is disposed between piston 510 and plunger 508.The interaction between piston 510, seal 518, and plunger 508 provides avalved interaction between the respective chambers of the shockassembly.

Sleeve 512 is sealingly supported between piston 510 and a sleeve base520 and generally defines a second chamber 526 of shock assembly 500.Plunger 508 includes a bypass section 522 that has a reducedcross-sectional area as compared to the remainder of the plunger 508.Bypass section 522 is constructed to pass through opening 516 of piston510 and cooperate with piston 510 in a manner that allows fluidcommunication between a first chamber 524 and the second chamber 526 ofshock assembly 500. Bypass section 522 allows plunger 508 to cooperatewith piston 510 in a non-sealing manner.

As shown in FIG. 20, when bypass section 522 is positioned in opening516 of piston 510, plunger 508 loosely cooperates with seal 518 therebyallowing fluid flow, indicated by arrow 523, between first chamber 524and second chamber 526 of shock assembly 500. Opposite ends of bypasssection 522 include swaged or transition portions 530 that provideguided interaction between plunger 508 and seal 518 of piston 510 asbypass section 522 passes through opening 516.

Referring back to FIGS. 14 and 15, fill valve assembly 514 can beselectively fluidly connected to a passage 540 defined by a sidewall 542of plunger 508. Gas introduced through fill valve assembly 514 isdirected directly to second chamber 526. During an initial oscillationof shock assembly 500, as bypass section 522 enters opening 516 formedin piston 510, a portion of the initial gas charge passes into firstchamber 524. As top tube 502 is allowed to extend away bottom tube 504,a lower portion 542 of plunger of plunger 508 interacts with opening 516of piston 510 and so as to fluidly isolate the first and second chambers524, 526 of shock assembly 500. Continued translation of top tube 502 ina direction away from bottom tube 504 allows the pressure of firstchamber 524 to continue to decrease while the pressure of second chamber526 is maintained at desired value.

During subsequent oscillation of shock assembly 500, the volume ofpassage 540 of plunger 508 and second chamber 526 contribute to thespring performance of shock assembly 500 only when top tube 502 andbottom tube 504 attain relative positions such that bypass section 522interacts with piston 510 thereby allowing fluid connectivity betweenthe first and second chambers 524, 526. As shown in FIG. 15, sleeve base520 includes a cavity 548 that is shaped and positioned to generallycooperate with an end portion 550 of plunger 508 as shock assembly 500approaches a fully compressed orientation. Such a construction allowsthe volume of plunger 508 to be selectively isolated from contributingto the nearly fully compressed spring performance of shock assembly 500.

FIG. 16 shows a shock assembly 600 according to another embodiment ofthe invention. The construction and operation of shock assembly 600 isgenerally similar to the description provided above with respect toshock assembly 500 except for the exclusion of sleeve 512. Shockassembly 600 includes a top tube 602 that slidably cooperates with thebottom tube 604. A first piston 606 and a second piston 608 are eachsupported by a compression rod 610. First piston 606 and second piston608 are attached to compression rod 610 in an offset manner so that asecond chamber 612 is formed therebetween. In a preferred embodiment, apair of clips 613, 615 are engaged with compression rod 610 on generallyopposite sides of second piston 608 so as to generally fix the positionof second piston 608 relative to first piston 606.

First piston 606 includes an opening 614 having a seal 616 andcooperates with a skewer or plunger 618 similar to plunger 508. Plunger618 includes a bypass section 620 that cooperates with opening 614formed in piston 606 so as to fluidly connected a first chamber 611 andsecond chamber 612. Plunger 618 is positioned within a cavity 622defined by compression rod 610. At least one vent or port 623 is formedin compression rod 610 and allows the volume of compression rod 610 tocontribute to the volume of second chamber 612. During sufficientoscillation of shock assembly 600, bypass section 620 cooperates withopening 614 of piston 606 thereby allowing fluid communication betweenfirst chamber 611 with cavity 622 of compression rod 610 and secondchamber 612 between pistons 606, 608.

It is appreciated that shock assembly 600 could be provided with a fillvalve assembly in accordance with any of the above embodiments. Forinstance, shock assembly 600 could be provided with a fill valveassembly similar to that described above with respect to shock assembly500. Alternatively, shock assembly 500 could be provided with anoptional plug 630 that cooperates with plunger 618. Understandably, sucha construction would require that the fill valve assembly communicatedirectly with one of first or second chambers 611, 612, or that plunger618 be provided with a port to facilitate fluid communication with oneof first or second chambers 611, 612. For instance, plunger 618 could beprovided with an internally connected fill valve assembly similar to thearrangement shown in FIG. 14 and a port that allows fluid communicationwith either of first chamber 611 or cavity 622 of compression rod 610.It is appreciated that such arrangements would require an initialoscillation of the shock assembly to allow first and second chambers611, 612 to attain their respective operating pressures.

FIGS. 17 and 18 show a shock assembly 700 according to yet anotherembodiment of the invention. Shock assembly 700 includes a top tube 702and a leg tube 703 that are telescopically associated and function in amanner similar to the shock assemblies previously described. However,unlike the previously described shock assemblies, shock assembly 700includes a gas based negative spring system rather than a coil springbased negative spring or bumper system such as bumper system 190 shownin FIG. 4.

A skewer or plunger 704 that is constructed similar to any of plungers402, 618, 800, 840, 880 slidably cooperates with a piston assembly 706that is positioned within top and leg tubes 702, 703. Piston assembly706 includes a main piston 710 that is attached to the shock assembly700 and offset from an end of leg tube 703 by a compression rod 710. Asecondary or negative piston 712 is slidably positioned aboutcompression rod 710. A deformable bumper 714 is disposed between mainpiston 710 and negative piston 712.

A bypass collar 720, a guide collar 722, and a cap 724 are attached tomain piston 710. Guide collar 722 includes an opening 726 thatcooperated with plunger 704 to allow the selective fluid communicationbetween a first chamber 728 and a second chamber 730 of shock assembly700 in a manner similar to that described above with respect to plungers402, 618, 800, 840, 880. Shock assembly 700 includes a third chamber 740that is fluidly isolated from first and second chambers 728, 730. Bypasscollar 720 includes one or more ports 734 that allow fluid communicationbetween a first cavity 736 and a second cavity 738 of third chamber 740.Third chamber 740 is generally sealed and provides a top out springcharacteristic as the volume of third chamber 740 is reduced by theoutward translation of top tube 702 relative to leg tube 703. As shockassembly 700 approaches a fully extended orientation, negative piston712 moves toward main piston 710 thereby compressing top out bumper 714as well as the volume of gas associated with third chamber 740. Thirdchamber 740 includes a first cavity 744 and a second cavity 746 that arefluidly connected by one or more passages 748 formed through bypasscollar 720. The volume of second cavity 746 that is enclosed by cap 724can be configured to provide a desired contribution to the top outbumper performance of shock assembly 700. Alternatively, duringassembly, third chamber 740 can be pressurized to attain a desired topout spring performance of shock assembly 700 without having a coilspring positioned proximate piston assembly 706.

The volume of first chamber 728 is defined by top tube 702 and cap 724and nearly the entirety of the second chamber 730 is defined bycompression rod 710. It is appreciated that the volume of plunger 704could be contributed to first chambers 728 by providing one or morefluid ports, similar to ports 404, 406 and a plug, similar to plug 630or contributed to second chamber by providing a non-ported or ventedbody having an open end that remains in fluid communication with thesecond chamber throughout the range of movement of the top and legtubes. Such a construction allows utilization of a greater portion ofthe volume enclosed by the top and leg tubes for the primary andsecondary chambers of the shock assembly and allows the secondarychamber to be formed nearly entirely by the compression rod. It isfurther appreciated that the performance of shock assembly 700 can bealtered by changing the diameter of either of the compression rod and/orthe plunger and that the top out spring performance can be manipulatedby altering the shape of cap 724.

FIG. 19 shows various skewers or plungers 800, 840, 880 for use withshock assemblies 400, 500, 600, 700. Comparing plungers 800 and 840, itcan be noted that the length of a bypass section 802 of plunger 800 isshorter than a length of a bypass section 842 of plunger 840. Thoseskilled in the art will appreciate that such a construction alters theperformance of a shock assembly equipped with either of plunger 800 or840 by altering the fluid connectivity between a first and secondchamber of the shock assembly. Said in another way, it is appreciatedthat plunger 840 will allow fluid communication between a first and asecond chamber of a respective shock assembly over a greater range oftranslation of a cap tube relative to the leg tube as compared toplunger 800. Accordingly, it is appreciated that the springcharacteristic of any of shock assemblies 400, 500, 600, 700 can bealtered by manipulating the length and position of bypass section 802,842, 882 relative to the length of the plunger, the relative travel ofthe cap tube and the leg tube, as well as the position of the bypasssection throughout the range of motion of the respective shock assembly.As described further below with respect to FIG. 21, providing a“shortened” period of fluid communication between the respectivechambers of the respective shock assemblies allows for a progressivespring response near the end of the spring curve.

As compared to plungers 800, 840, plunger 880 has a thicker wallconstruction and a narrower passage formed through an interior thereof.Plunger 880 includes a bypass or bypass section 882 that can begenerally asymmetrical with respect to the cross section of plunger 800and can be milled or machined into the sidewall of the plunger ascompared to the swaged sections associated with plunders 800, 840.Plunger 880 has a fairly robust construction and the asymmetric natureof bypass section 882 allows plunger 880 to be maintained in a fairlyconcentric position with respect to a longitudinal axis of thecorresponding piston. Furthermore, although bypass 882 of plunger 880 isshown to include two generally oppositely positioned grooves 884 thatextend along bypass section 882, it is envisioned that bypass section882 could include any number of grooves or flutes such as one or morethan two and provide a desired fluid connectivity between the first andsecond chambers of a respective shock assembly.

It is further appreciated that the interior shape of plungers 800, 840,880 can be oriented to contribute to or alter the spring performance ofa shock assembly equipped therewith. For instance, for those embodimentswherein the interior cavity of the plunger contributes to the volume ofeither of the first or second chamber of the shock assembly, plungers800, 840 will provide a more compliant spring performance as compared toa comparable shock assembly equipped with plunger 880 due to the reducedvolume thereof. In a similar manner, it is also appreciated that thereduced cross-sectional area of the interior passage of plunger 880 canprovide a more resistive shock performance when plunger 800 isincorporated into those embodiments of shock assemblies 400, 500, 600,700 that rely on fluid communication through the interior of the plungerto facilitate fluid communication between the first and second chambersof the respective shock assemblies. Preferably, the springcharacteristics and speed sensitivity, as described further below, canbe tailored to provide a desired response by altering the shape/volumeassociated with the bypass section. It is further envisioned that thebypass section can be positioned so that fluid connectivity between thefirst and second chambers is allowed only during a desired range ofposition of a top tube relative to a bottom tube of a respective shockassembly. As described further below, in preferred embodiments,regardless of the construction of the plunger and its cooperation withthe piston, shock assemblies according to the present invention allowthe selective coupling and decoupling of the contribution of the secondchamber to the performance of the shock assembly.

Still referring to FIG. 19, it can be seen that, if each of plungers800, 840, and 880 were provided in a respective similarly configuredshock assembly, the first and second chambers of the shock assemblyequipped with plunger 840 would be in fluid communication for a greaterduration over the entire travel of the shock assembly by virtue ofbypass 842 extending a greater length of plunger 840 than acorresponding length of extension of bypasses 802, 882 of plungers 800,880. Preferably, bypass section 842 is in effect or allows fluidcommunication between the respective chambers of a shock assembly whenthe top tube and bottom or leg tube are from between approximately 66%of a total available compressive travel and the respective shockassemblies fully compressed relative travel. Said in another way, bypasssection 842 allows fluid communication between the first and secondchambers when the shock assembly is between about 66% and 100% a fullycompressed orientation. Comparatively, bypass section 802 is in effectbetween about approximately 66% and 92% of a fully compressedorientation. An upper portion 804 of plunger 800 and an upper portion886 of plunger 880 terminates the fluid communication between the firstand second chamber of shock assembly so as to isolate the contributionof the second chamber from the spring performance of the shock assemblyduring a final portion, i.e. from about 92% to 100%, of the totaltranslation of the shock assembly. Preferably, upper portion 804, 886are positioned to effectuate fluid isolation between the first andsecond chambers when the shock assembly is between about 83% to about92% from an at rest configuration of the top and leg tubes of therespective shock assembly. As described below with respect to FIG. 21,such a construction provides a shock assembly having a progressivespring response as the shock assembly approaches a near fullcompression.

It is further appreciated that the bypass fluid performance arrangementsdescribed above are applicable across a range of product platforms andare not specific to translation of a given shock orientation. That is,it is appreciated that the present invention is applicable to shockassemblies having a number of ranges of operation including the fairlycommon configurations wherein the top tube and leg tube facilitatetranslations in the range of about 100 mm (about 3.93 inches), 120 mm(about 4.72 inches), and about 140 mm (about 5.52 inches). These valuesare given by way of example and it is appreciated that shock operatingranges other than these common parameters are envisioned.

As shown graphically in FIG. 21, the force to displacement performanceof each of plungers 800, 840, 880 is very nearly comparable over amajority of the travel of a corresponding shock assembly. Trend 888 isindicative of the performance of a shock assembly equipped with aplunger having a shorter bypass or a bypass that terminates along theplunger in a manner such that fluid isolation can be achieved before theshock assembly attains a fully compressed condition. Trend 890 isindicative of a similar shock assembly equipped with a plunger having alonger bypass section.

With respect to trend 888, as the respective shock assembly approaches afully compressed, i.e., a shortening of the overall length of the shockassembly, those shock assemblies equipped with a shortened bypasssection, such as plungers 800, and 880, terminate the fluidcommunication between the first and second chambers thereby providing amore progressive spring response, indicated by portion 892 of trend 888,near the end of the full travel of the shock assembly. Comparatively,trend 890 provides a fairly linear force to displacement responsethrough nearly the entire range of travel of the shock assembly. Asindicated by those portions of trends 888, 890 beyond roughly 4 inchesof shock travel, shock assemblies equipped with shortened bypasssections allow the respective shock assemblies to accommodate greaterforces through the final translations of the shock assemblies ascompared to those shock assemblies that do not decouple the fluidconnectivity between the first and second chambers at a configurationthat is deep into the overall travel of the shock assembly.

It is further appreciated that shock assemblies having ported plungerssuch as that shown in FIG. 22 can be configured in a similar manner.That is, as described above, ports 404, 406 of plunder 402 can bepositioned nearer ports 408, 410 so that the first and second chambers430, 428 are allowed to fluidly couple and decouple throughout a singletravel direction of shock assembly 400. Said in another way, when eachof ports 404, 406, 408, 410 are positioned on a common side of piston418, only first chamber 430 contributes to the spring performance ofshock assembly 400 such that the results associated with trend 888 canbe attained with either of a ported plunger, such as plunger 402, or aplunger having an external bypass section, such as plungers 800, 880.

FIG. 23 shows graphically speed sensitivities that can be achieved withvarious shock assemblies according to the present invention. The speedsensitivity correlates the velocity of the plunger shaft, and therebythe rate of change of position of the top tube relative to the bottomtube, and the spring characteristics of the shock assembly. As shown inFIG. 23, the various shock assemblies have comparable force todisplacement ratios when the two chambers are not fluidly connected—fordisplacements that are less than about 66% of available travel in thiscase—for speed sensitivities of about 1 inch per second to about 40inches per second. For shock displacements above about 66% of availabletravel, when the two chambers are fluidly connected, the speedsensitivity deviates from a more linear response at lower shaftvelocities of about 1 inch per second to more progressive speedsensitivities as the shaft velocities increases to about 40 inches persecond. Said in another way, the various trends shown in FIG. 23evidence the decoupling of the fluid connectivity between the first andsecond chambers of the respective shock assemblies as the shockassemblies experience travels over 66% of available travel for thoseshocks that are constructed to allow the fluid decoupling of the secondchamber deep in the travel of the shock assembly. As the speed ofcompression of the shock assembly increases, the spring performance ofthe shock assembly provides a more progressive response to the continuedcompression of the shock assembly as the rate of the compressionincreases. Such a construction allows the shock assemblies to providecompressibility at higher shock force loadings. As such, the shockassemblies improve rider comfort by providing a greater operating rangeof the respective shock assemblies.

It is further appreciated that the speed sensitivity of the variousshock assemblies disclosed herein can also be manipulated by changingthe cross sectional area associated with the respective bypass sections.That is, constructing the shock assemblies to have a bypass section thatallows fairly un-restricted fluid communication between the firstchamber and the second chamber will provide a lower level of availablespeed sensitivity than a shock assembly having a somewhat restrictivebypass section, such as a ported plunger having only a single port thatallows fluid communication between the first and second chambers. Thesingle port restricts the fluid flow between the first and secondchambers and thereby increases the available range of the speedsensitivity of the shock assembly. Providing a lesser restrictive bypasssection, such as with a larger swaged section to out diameter plungerratio or a number of first and second chamber ports, increases the areaavailable for fluid communication between the first and second chambersthereby decreasing the speed sensitivity of the shock assembly over theavailable translation. The spring curve of such a shock assembly wouldcontinue to be more linear as shaft velocities increased as compared toa shock assembly having a more restrictive bypass section. Accordingly,the speed sensitivity of the various shock assemblies can also beadjusted by manipulating the area associated with the bypass section aswell as the position of the bypass section relative to shock travel asdiscussed above. Said in another way, speed sensitivity can be increasedas the area associated with a respective bypass section of a respectiveshock assembly is decreased. The shock assemblies disclosed herein canbe uniquely configured to satisfy a variety of user demands as well as avariety of operating ranges and preferences.

Each shock assembly described above provides a shock absorber wherein afirst tube is movable relative to a second tube. After a selecteddisplacement relative to the two tubes, a second volume is fluidlyconnected to a first volume and thereby alters the performance of theshock assembly during translation of the tubes beyond selecteddisplacements. Each shock assembly provides a dual chamber shock havinga valved interface that separates the chambers and whose operation isnon-fluidly controlled. The plunger of each shock assembly non-fluidlyovercomes the closed bias of the valve arrangements. By physicallymanipulating the valve arrangements, each of the heretofore describedshock assemblies provide a shock that can be conveniently configured foroperation at individual preferences and which provides improved shockperformance across a wider range of the total length of displacement ofthe shock assembly. Such preferable structure further enhances thefunctionality of the respective shocks.

Therefore, one embodiment of the invention includes a bicycle shockassembly that has a first sleeve and a second sleeve. The second sleeveis engaged with the first sleeve such that the first sleeve and thesecond sleeve are connected in a telescopic manner. A piston is enclosedby the first and second sleeves and defines a first volume on one sideof the piston and a second volume on an opposite side of the piston. Avalve arrangement is formed between the first and second volumes andconfigured to fluidly separate the first volume from the second volume.A plunger is configured to cooperate with the piston to selectively openthe valve arrangement to fluidly connect the second volume to the firstvolume.

Another embodiment of the invention usable with one or more of thefeatures associated with the above embodiment includes a method ofaltering the in-use performance of a bicycle shock. The method includesforming a first chamber and a second chamber that are separated by apiston. The first and second chambers are selectively fluidly connectedas a function of translation of a cap tube relative to a leg tube bytranslating a plunger through an opening formed in the piston.

Another embodiment of the invention useable with one or more of theaspects or embodiments includes a bicycle suspension system having a captube attached to a first bicycle structure and a leg tube attached to asecond bicycle structure. The cap tube and the leg tube aretelescopically associated to allow translation between the first andsecond bicycle structures. A piston that separates a first volume from asecond volume is disposed in a cavity enclosed by the cap and leg tubes.The piston encloses the first volume whose pressure increases as distalends of the cap and leg tubes move toward one another. A plungercooperates with the piston to fluidly connect the first and secondvolumes when the distal ends of the cap and leg tubes are a selecteddistance apart.

It is further appreciated that one or more aspects of the variousembodiments of the invention can be combined with one or more featuresof the various embodiments to achieve shock constructions,configurations, and operations other than the preferred configurationsthat have been described above. The forthcoming claims are intended toencompass all such deviations and combinations of the respectivefeatures disclosed herein. That is, no one aspect of the presentinvention is exclusive to the particular embodiment within which suchaspect is discussed.

The present invention has been described in terms of the preferredembodiments, and it is recognized that equivalents, alternatives, andmodifications, aside from those expressly stated, are possible andwithin the scope of the appending claims. It is further appreciated thatthe respective features of any one of the embodiments discussed above isnot necessarily solely exclusive thereto. Aspects of one or more of theembodiment may be equally applicable to other embodiments. That is, asdescribed in the forth coming claims, the invention includes all of theembodiments as well as aspects specific thereto.

What is claimed is:
 1. A shock assembly for a bicycle comprising: afirst sleeve; a second sleeve engaged with the first sleeve such thatthe first sleeve and the second sleeve are connected in a telescopicmanner and are configured to translate through a stroke; a pistonenclosed by the first and second sleeves and defining a first positivegas volume on one side of the piston and a second positive gas volume onan opposite side of the piston, wherein the first positive gas volumeand the second positive gas volume are configured to increase pressurein a same one direction of the translation and decrease pressure in thesame other direction of the translation; a valve arrangement formedbetween the first and second positive gas volumes and configured tofluidly separate the first positive volume from the second positivevolume; and a plunger configured to cooperate with the piston toselectively open the valve arrangement to fluidly connect the secondpositive gas volume to the first positive gas volume; wherein the valvearrangement and the plunger are configured to: isolate the firstpositive gas volume and the second positive gas volume during a firsttranslation range of the stroke of the first sleeve and the secondsleeve; fluidly couple the first positive gas volume and the secondpositive gas volume during a second translation range of the stroke ofthe first sleeve and the second sleeve; the stroke traverses a distancefrom a state where the second sleeve is fully compressed into the firstsleeve to a state where the second sleeve is fully extended from thefirst sleeve; the stroke includes the first translation range and thesecond translation range; and the first translation range and the secondtranslation range do not overlap in single direction of the stroke. 2.The shock assembly of claim 1, wherein the plunger extends from one ofan end of one of the first sleeve, an end of the second sleeve or thevalve arrangement.
 3. The shock assembly of claim 1, wherein the valvearrangement is formed by cooperation of the plunger with the piston; andthe first translation range and the second translation range arearranged consecutively in the stroke.
 4. The shock assembly of claim 1,wherein the valve arrangement is formed by cooperation of the plungerwith the piston, the plunger includes a bypass section that allows fluidcommunication between the first positive gas volume and the secondpositive gas volume, and the first positive gas volume and the secondpositive gas volume are configured as a spring.
 5. The shock assembly ofclaim 4, wherein the bypass section is formed by one of an exteriorcontour of the plunger or a number of ports that are spaced along alongitudinal length of the plunger.
 6. The shock assembly of claim 4,wherein the plunger is hollow.
 7. The shock assembly of claim 6, whereina volume of the plunger contributes to the second positive gas volume.8. The shock assembly of claim 1, wherein the plunger is configured tocooperate with the piston to selectively open the valve arrangement toprovide one of a plurality of rates of fluid communication between thefirst positive gas volume and the second positive gas volume.
 9. Theshock assembly of claim 1, further comprising a fill valve assemblysupported by one of the first and second sleeves for pressurizing thefirst positive gas volume.
 10. The shock assembly of claim 9, whereinthe fill valve assembly can be selectively fluidly disposed between thesecond positive gas volume and atmosphere.
 11. The shock assembly ofclaim 9, wherein the fill valve assembly is movable to selectively fillthe first positive gas volume, the second positive gas volume, or thefirst positive gas volume and the second positive gas volume.
 12. Theshock assembly of claim 1, further comprising a first shock assembly anda second shock assembly that support generally opposite lateral sides ofa wheel axle.
 13. The shock assembly of claim 1, wherein the valvearrangement and the plunger are further configured to isolate the firstpositive gas volume and the second positive gas volume during a thirdtranslation range of the first sleeve and the second sleeve.
 14. Abicycle suspension system comprising: a cap tube attached to a firstbicycle structure; a leg tube attached to a second bicycle structure,the cap tube and the leg tube being telescopically associated to allowtranslation between the first and second bicycle structures, and the captube and the leg tube are configured to translate through a stroke; apiston disposed in a cavity enclosed by the cap and leg tubes forenclosing a first positive gas volume whose pressure increases as distalends of the cap and leg tubes move toward one another and separating thefirst positive gas volume from a second positive gas volume wherein thefirst positive gas volume and the second positive gas volume areconfigured to increase pressure in a same one direction of thetranslation and decrease pressure in the same other direction of thetranslation; and a plunger that cooperates with the piston; wherein theplunger and the piston are configured to: isolate the first positive gasvolume and the second positive gas volume during a first translationrange of the stroke of the cap tube and the leg tube; fluidly couple thefirst positive gas volume and the second positive gas volume during asecond translation range of the stroke of the cap tube and the leg tube;the stroke traverses a distance from a state where the leg tube is fullycompressed into the cap tube to a state where the leg tube is fullyextended from the cap tube; and the stroke includes the firsttranslation range and the second translation range.
 15. The suspensionsystem of claim 14, wherein the plunger extends through the pistontoward the distal end of the cap tube and includes a bypass section thatallows fluid communication between the first and second positive gasvolumes; and the first translation range and the second translationrange are arranged consecutively in the stroke.
 16. The suspensionsystem of claim 15, wherein the bypass section allows fluid flow betweenthe first and second positive gas volumes between the plunger and thepiston or through a passage within the plunger.
 17. The suspensionsystem of claim 15, wherein the bypass section forms an area of fluidconnectivity between the first and second positive gas volumes, the areabeing inversely associated with a speed sensitivity of the suspensionsystem.
 18. The suspension system of claim 15, wherein the bypasssection allows fluid communication between the first and second positivegas volumes along a middle portion of a stroke of movement of the captube relative to the leg tube.
 19. The suspension system of claim 14,further comprising a fill valve assembly for connecting one of the firstand second positive gas volumes to atmosphere.
 20. The suspension systemof claim 19, wherein the fill valve assembly is one of disposed betweenthe first positive gas volume and atmosphere or disposed between thesecond positive gas volume and atmosphere.
 21. The suspension system ofclaim 19, wherein the fill valve assembly is configured to selectivelyconnect at least one of the first positive gas volume to atmosphere, thesecond positive gas volume to atmosphere, and the first positive gasvolume and the second positive gas volume to atmosphere.
 22. Thesuspension system of claim 14, wherein the plunger and the piston arefurther configured to isolate the first positive gas volume and thesecond positive gas volume during a third translation range of the firstsleeve and second sleeve.
 23. A method of altering in use performance ofa bicycle shock comprising: forming a first positive gas chamber and asecond positive gas chamber that are separated by a piston; andselectively fluidly connecting the first positive gas chamber and thesecond positive gas chamber as a function of translation of a cap tuberelative to a leg tube by translating a plunger through an openingformed in the piston, and the cap tube and the leg tube are configuredto translate through a stroke, wherein the first positive gas volume andthe second positive gas volume are configured to increase pressure in asame one direction of the translation and decrease pressure in the sameother direction of the translation; wherein: the first positive gaschamber and the second positive gas chamber are isolated during a firsttranslation range of the stroke of the cap tube and the leg tube, thefirst positive gas chamber and the positive second gas chamber arefluidly coupled during a second translation range of the stroke of thecap tube and the leg tube; the first translation range and the secondtranslation range do not overlap in the stroke; the stroke traverses adistance from a state where the leg tube is fully compressed into thecap tube to a state where the leg tube is fully extended from the captube; and the first translation range and the second translation rangeare arranged consecutively and in a single direction within the stroke.24. The method of claim 23, further comprising providing a valveassembly that allows pressurization of at least one of the firstpositive gas chamber and the second positive gas chamber.
 25. The methodof claim 23, further comprising adjusting a speed sensitivity of thebicycle shock by changing a rate of fluid communication between thefirst and second positive gas chambers.
 26. The method of claim 23,wherein the first positive gas chamber and the second positive gaschamber are isolated during a third translation range of the cap tubeand the leg tube.